The FFR, FIR, IRFU, SRU and WRU have committed to participating in the European Rugby Cup next season under a new format.
The meeting was attended in Dublin by all Unions apart from the RFU, who voiced their "surprise and disappointment" at being excluded.
A new 20-team version of the Heineken Cup has been agreed upon by the remaining five countries.
Previously the Aviva Premiership clubs, Top 14 clubs and Welsh regions have all pledged their support to the breakaway Rugby Champions Cup tournament, putting the FFR and WRU now at loggerheads with their domestic teams.
"A meeting was held in Dublin today, attended by FFR, FIR, IRFU, SRU and WRU, to discuss the on-going issues surrounding European club competitions," read a statement issued by the five Unions.
"All five Unions believe that it is critical to the interests of the game in Europe that the Unions are at the heart of the governance of cross-border club competitions given that rugby in each country is organised in a pyramidical structure.
"Clubs, provinces and regional organisations form an integral part of the development of the game throughout this structure, from grassroots to the international game. Cross-border club competitions must not conflict with the development of the sport in Europe by Unions, this being in the best interest of players, spectators and the sport in general.
"The five Unions reconfirmed:
• Their agreement with the new competition formats and financial distribution formula previously agreed by the six Unions who attended the mediated meeting in Dublin on 23-24 October.
Following today's discussions, the five Unions have agreed the following:
• A European club competition is to take place during the 2014/2015 season following an optimised sporting and economic format with 20 teams, no matter how many countries are involved.
• The competition will be driven by the existing organisation (currently named ERC) which will remain in charge of the centralised sale and management of all commercial rights, amongst other things.
• Discussions over governance will be pursued in order to optimise the internal functioning of the existing organisation (currently named ERC).
• The common aim is to move eventually towards the integration of European competitions within an all-encompassing European rugby framework."
In response, Premiership Rugby re-iterated that nothing has changed regarding the English and French clubs' decision to leave the ERC.
"Premiership Rugby notes the statement issued this evening concerning the proposed new European club rugby competitions for the 2014/15 season," read a statement.
"There is no detail concerning the teams involved or the competition format given the absence of so many teams.
"The English and French clubs served notice on ERC and its competitions on 1st June 2012 and the required notice period concludes after the end of this season when the Accord will terminate.
"Today's announcement would appear to indicate that the latest negotiations have been ended, as was the case in September 2013.
"As a result, we shall continue to implement the plans underway for the Rugby Champions Cup with the declared participants in time for the 2014-15 season, as required by our clubs and communicated in the joint statement of 10 September 2013 and subsequent media statements.
"The two new competitions will be based on:
* Qualification on merit
* A strong competition format
* Equality between the leagues
* Higher commercial values for the teams
* Expansion into new markets."